build(deps): bump third_party/gflags from `986e8ee` to `03a4842` (#2380)

Bumps [third_party/gflags](https://github.com/gflags/gflags) from `986e8ee` to `03a4842`.
- [Release notes](https://github.com/gflags/gflags/releases)
- [Commits](https://github.com/gflags/gflags/compare/986e8eed00ded8168ef4eaa6f925dc6be50b40fa...03a4842c9c6aaef438d7bf0c84e8a62c8064992b)

---
updated-dependencies:
- dependency-name: third_party/gflags
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/gflags b/third_party/gflags
index 986e8ee..03a4842 160000
--- a/third_party/gflags
+++ b/third_party/gflags
@@ -1 +1 @@
-Subproject commit 986e8eed00ded8168ef4eaa6f925dc6be50b40fa
+Subproject commit 03a4842c9c6aaef438d7bf0c84e8a62c8064992b